Update tools/flakes to work with pydoc

Change-Id: Ib141553017aa88d6edb65b5d51c06740699a2480

flakes.py

@@ -1,22 +1,22 @@
-import __builtin__
-import os
-import sys
-
-from pyflakes.scripts.pyflakes import main
-
 """
  wrapper for pyflakes to ignore gettext based warning:
      "undefined name '_'"
 
  From https://bugs.launchpad.net/pyflakes/+bug/844592
 """
+import __builtin__
+import os
+import sys
 
-names = os.environ.get('PYFLAKES_BUILTINS', '_')
-names = [x.strip() for x in names.split(',')]
-for x in names:
-    if not hasattr(__builtin__, x):
-        setattr(__builtin__, x, True)
+from pyflakes.scripts.pyflakes import main
 
-del names, os, __builtin__
+if __name__ == "__main__":
+    names = os.environ.get('PYFLAKES_BUILTINS', '_')
+    names = [x.strip() for x in names.split(',')]
+    for x in names:
+        if not hasattr(__builtin__, x):
+            setattr(__builtin__, x, True)
 
-sys.exit(main())
+    del names, os, __builtin__
+
+    sys.exit(main())